This domain family is found in eukaryotes, and is approximately 40 amino acids in length. The family is found in association with pfam00069. These proteins are involved in inflammatory reactions. They cause release of NF-kappa-B into the nucleus of inflammatory cells and upregulation of transcription of proinflammatory cytokines. They perform this function by phosphorylating I-kappa-B proteins which are targeted for degradation to release NF-kappa-B. This kinase (I-kappa-kinase-beta) is found in association with IKK-alpha and NEMO (NF-kappa-B essential modulator). This domain is the binding site of IKK-beta for NEMO.